This invention relates to improvements in the sheep shearing industry and in particular relates to means for mechanically lifting a sheep from the floor and means for holding the sheep in that position for a shearer to shear it.
Sheep are generally shorn by a shearer who, whilst holding the sheep on the floor, straddles the sheep and removes the fleece according to common practice with a pair of hand-held shears. This means that the shearer is bending over the sheep whilst shearing it, which requires strength and stamina on the part of the shearer to restrain the sheep whilst he shears it. Furthermore, he must at all times keep one hand on the sheep whilst wielding the cutting shears with the other. As the sheep struggles it is likely that at least minor nicks and grazes will result.
It would therefore be highly desirable to provide a lifting arrangement suitable for holding a sheep which is to be shorn and raising it to the equivalent of bench height or thereabouts, which overcomes some of the recognised shortcomings in manipulating a sheep whilst shearing it according to current practice. To this end, a lifting jack has been devised which overcomes or at least ameliorates some of the foregoing disadvantages of present shearing techniques. At the very least, the invention provides an alternative to the present practice of shearing sheep whilst bending over them and holding them by hand.
According to the present invention there is provided a lifting jack for shearing sheep, which comprises a cradle for holding a sheep on its back or stomach and which is shaped so as to allow the sheep to be rolled from its back to its stomach or vice versa during the shearing operation, lifting means in the form of a chain and sprocket mechanism to move the cradle from a first loading/unloading position adjacent the floor of a shearing shed or other suitable location for shearing sheep and a second raised position for shearing the sheep approximating the height of a work bench so that the sheep is able to be lifted whilst it is shorn in order that the shearer avoids bending over the sheep, the lifting means being operable by a suitably located foot pedal between the first loading/unloading position and second shearing position by a single unassisted shearer, so that in use a shearer is able to place a sheep in the cradle at floor height and whilst either holding the sheep himself or otherwise restraining the sheep with a chain or belt or the like is then able to cause the cradle to be lifted, and wherein locking means are provided in association with the foot pedal so that after a predetermined length of travel corresponding to the required raising of the cradle, the pedal can be locked in its lower position, without the need for the shearer to keep his foot thereon, thereby preventing the cradle from returning to its first loading/unloading position until shearing has been completed when the locking mechanism is released to allow the cradle to be returned.
Preferably, the cradle is provided with restraining means, for example in the form of a chain which can be passed over the sheep and located over some suitable projection or hook or alternatively the restraining means comprises a belt which may be fastened by known means, to allow the sheep to be restrained for at least part of the shearing process so that the sheerer is able for at least part of the shearing operation to have both hands free of the sheep.
Thus, the lifting means of the shearing lifting jack comprises a chain and sprocket mechanism operable by a suitably located foot pedal, so that in use a shearer is able to place a sheep in the cradle at floor height and whilst either holding the sheep himself or otherwise restraining the sheep with a chain or belt as described above is then able to cause the cradle to be lifted.
For example a simple chain drawn over a single sprocket, where the chain is affixed at or near one end to the cradle and the where other end is attached to s foot or hand operable pedal, will allow the shearer to push down on the raised pedal, when the sheep is loaded to the cradle, thereby causing the cradle to lift as the pedal is pushed down. Preferably the weight of the cradle and sheep will be offset to a reasonable degree by the weight of the foot pedal (ie they will be in rough equilibrium with the greater weight provided by the cradle and sheep) so that the effort required to raise or lower the sheep is lessened.
Preferably the looking means is provided in the form of a notched plate pivotally attached to the pedal which may be slid into locking engagement with a suitable projection located for the purpose on the shearing lifting jack so that the pedal is locked in its lower position whilst the cradle is in its second shearing position.
As an alternative to the aforementioned manual operation, the lifting means may be operated by means of a suitable motor. Thus for example, in addition to the aforementioned chain and socket arrangement as described above, there is provided a second chain which is connected between the foot pedal and cradle or the ends of the first chain itself to form a continuous loop with the first chain (ie the pedal and cradle either being the points of attachment for the respective ends of the two chains or where the chains themselves are otherwise suitably connected, the cradle and/or foot pedal may be suitably attached to appropriate portions of the chain as required).
In this embodiment, a second sprocket is suitably positioned in relation to the second chain so that a motor either directly or indirectly operates on the second sprocket to cause the whole chain assembly (comprising both chain portions) and hence the cradle to move. In this embodiment, the motor itself, may act as a brake to prevent return of the cradle to the first loading position. It will also be appreciated that the foot pedal itself may in fact be removed altogether as it is effectively redundant. However, with advantage, it may be useful to incorporate it in the design of such a jack to facilitate operation thereof when power is not available, or at least readily available, in the field. In addition the foot pedal may provide added safety by allowing manual locking of the jack in addition to the braking afforded by the motor.
It will also be readily appreciated that it would be advantageous to provide isolating switches located at suitable positions (eg which are contacted by the cradle at the end of its travel) so that the motor is stopped or otherwise disengaged (eg by suitable clutch means) from driving the sprocket and chain assembly so that travel thereof is limited and hence the cradle, and where it exists the foot pedal, are prevented from causing damage through further unwanted motion, or the motor itself is prevented from being damaged.
Preferably, the chain and sprocket arrangement of either embodiment is housed in a substantially upright support housing in the form of a hollow post which protects the chain and sprocket both from the point of view of safety and in order to keep it clean. More preferably the support housing or post has substantially vertical slots located therein on opposite sides thereof, which form guides or tracks through which extend connecting means to support the cradle on one side of the housing and to support or connect with the foot pedal on the other side. These connecting means are preferably provided with suitable means to assist their sliding in the aforementioned guides or tracks, for example in the form of suitable located wheels which run on the internal and/or external surface of support housing.
With advantage, the shearing lifting jack is also provided with suitable support means in the form of a base plate which can be affixed to the floor and which supports the substantially vertical or upright structure or post which houses the chain and sprocket mechanism and from which extend the cradle and foot pedal.
Other means of motor drive apart from an individual motor connected to the jack are also contemplated, for example involving power derived from suitable belt and pulley systems as found in shearing sheds and the like, where by suitable modification the invention may also be employed.
A shearing lifting jack, according to one embodiment of the invention, is preferably of metal design, constructed primarily from mild steel and employing high engineering tolerances in its construction. The shearing lifting jack is preferably made from steel plate of sufficient quality to ensure that it remains robust. The shearing lifting jack of this embodiment is relatively heavy being around 83 kg, although its weight will depend on the particular gauges etc of the materials specified. This weight helps the shearing lifting jack remain in a stable position during use. The overall height of the shearing lifting jack is preferably around 1030 mm. It needs no more that one square meter of floor space. Thus a shearer needs only 1 sq m of space in the shearing shed when operating the shearing lifting jack, allowing for both the shearer himself and the sheep as well as the jack, although in practice it is preferable to allow say a space of 1.5 sq m per jack. One jack is utilised per shearer With advantage, the shearing lifting jack is affixed to the floor with screws for a wooden floor or with bolts for a concrete floor. It must be remembered that the sheerer is dealing with untrained animals in the form of sheep of varying size and weight from 15 to 140 kg. However, working with this lifting jack makes it very easy for the shearer.
The invention is designed to help a shearer accomplish the job of shearing faster and more easily. A shearer utilising the jack according to the invention will have both legs free and he will be working in a vertical position like a person working at a bench rather than having to bend over the sheep. He will be able to easily drag a sheep onto the towered cradle, the sheep being initially located in an upturned manner. Here he will be able to attend to the shearing of the neck, head, legs and under belly of the sheep; before turning the sheep over on its back to complete the shearing operation. The time for a shearer to bring a sheep onto the stand and lift it with this invention will generally be no longer than about 10 seconds.